1 files changed, 368 insertions, 0 deletions
diff --git a/src/librbd/image/SetSnapRequest.cc b/src/librbd/image/SetSnapRequest.cc
new file mode 100644
index 000000000..fbc234aef
--- /dev/null
+++ b/src/librbd/image/SetSnapRequest.cc
@@ -0,0 +1,368 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "librbd/image/SetSnapRequest.h"
+#include "common/dout.h"
+#include "common/errno.h"
+#include "librbd/ExclusiveLock.h"
+#include "librbd/ImageCtx.h"
+#include "librbd/ObjectMap.h"
+#include "librbd/Utils.h"
+#include "librbd/image/RefreshParentRequest.h"
+#include "librbd/io/ImageDispatcherInterface.h"
+
+#define dout_subsys ceph_subsys_rbd
+#undef dout_prefix
+#define dout_prefix *_dout << "librbd::image::SetSnapRequest: "
+
+namespace librbd {
+namespace image {
+
+using util::create_context_callback;
+
+template <typename I>
+SetSnapRequest<I>::SetSnapRequest(I &image_ctx, uint64_t snap_id,
+                                  Context *on_finish)
+  : m_image_ctx(image_ctx), m_snap_id(snap_id), m_on_finish(on_finish),
+    m_exclusive_lock(nullptr), m_object_map(nullptr), m_refresh_parent(nullptr),
+    m_writes_blocked(false) {
+}
+
+template <typename I>
+SetSnapRequest<I>::~SetSnapRequest() {
+  ceph_assert(!m_writes_blocked);
+  delete m_refresh_parent;
+  if (m_object_map) {
+    m_object_map->put();
+  }
+  if (m_exclusive_lock) {
+    m_exclusive_lock->put();
+  }
+}
+
+template <typename I>
+void SetSnapRequest<I>::send() {
+  if (m_snap_id == CEPH_NOSNAP) {
+    send_init_exclusive_lock();
+  } else {
+    send_block_writes();
+  }
+}
+
+template <typename I>
+void SetSnapRequest<I>::send_init_exclusive_lock() {
+  {
+    std::shared_lock image_locker{m_image_ctx.image_lock};
+    if (m_image_ctx.exclusive_lock != nullptr) {
+      ceph_assert(m_image_ctx.snap_id == CEPH_NOSNAP);
+      send_complete();
+      return;
+    }
+  }
+
+  if (m_image_ctx.read_only ||
+      !m_image_ctx.test_features(RBD_FEATURE_EXCLUSIVE_LOCK)) {
+    int r = 0;
+    if (send_refresh_parent(&r) != nullptr) {
+      send_complete();
+    }
+    return;
+  }
+
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << dendl;
+
+  m_exclusive_lock = ExclusiveLock<I>::create(m_image_ctx);
+
+  using klass = SetSnapRequest<I>;
+  Context *ctx = create_context_callback<
+    klass, &klass::handle_init_exclusive_lock>(this);
+
+  std::shared_lock owner_locker{m_image_ctx.owner_lock};
+  m_exclusive_lock->init(m_image_ctx.features, ctx);
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::handle_init_exclusive_lock(int *result) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << ": r=" << *result << dendl;
+
+  if (*result < 0) {
+    lderr(cct) << "failed to initialize exclusive lock: "
+               << cpp_strerror(*result) << dendl;
+    finalize();
+    return m_on_finish;
+  }
+  return send_refresh_parent(result);
+}
+
+template <typename I>
+void SetSnapRequest<I>::send_block_writes() {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << dendl;
+
+  m_writes_blocked = true;
+
+  using klass = SetSnapRequest<I>;
+  Context *ctx = create_context_callback<
+    klass, &klass::handle_block_writes>(this);
+
+  std::shared_lock owner_locker{m_image_ctx.owner_lock};
+  m_image_ctx.io_image_dispatcher->block_writes(ctx);
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::handle_block_writes(int *result) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << ": r=" << *result << dendl;
+
+  if (*result < 0) {
+    lderr(cct) << "failed to block writes: " << cpp_strerror(*result)
+               << dendl;
+    finalize();
+    return m_on_finish;
+  }
+
+  {
+    std::shared_lock image_locker{m_image_ctx.image_lock};
+    auto it = m_image_ctx.snap_info.find(m_snap_id);
+    if (it == m_image_ctx.snap_info.end()) {
+      ldout(cct, 5) << "failed to locate snapshot '" << m_snap_id << "'"
+                    << dendl;
+
+      *result = -ENOENT;
+      finalize();
+      return m_on_finish;
+    }
+  }
+
+  return send_shut_down_exclusive_lock(result);
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::send_shut_down_exclusive_lock(int *result) {
+  {
+    std::shared_lock image_locker{m_image_ctx.image_lock};
+    m_exclusive_lock = m_image_ctx.exclusive_lock;
+  }
+
+  if (m_exclusive_lock == nullptr) {
+    return send_refresh_parent(result);
+  }
+
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << dendl;
+
+  using klass = SetSnapRequest<I>;
+  Context *ctx = create_context_callback<
+    klass, &klass::handle_shut_down_exclusive_lock>(this);
+  m_exclusive_lock->shut_down(ctx);
+  return nullptr;
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::handle_shut_down_exclusive_lock(int *result) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << ": r=" << *result << dendl;
+
+  if (*result < 0) {
+    lderr(cct) << "failed to shut down exclusive lock: "
+               << cpp_strerror(*result) << dendl;
+    finalize();
+    return m_on_finish;
+  }
+
+  return send_refresh_parent(result);
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::send_refresh_parent(int *result) {
+  CephContext *cct = m_image_ctx.cct;
+
+  ParentImageInfo parent_md;
+  bool refresh_parent;
+  {
+    std::shared_lock image_locker{m_image_ctx.image_lock};
+
+    const auto parent_info = m_image_ctx.get_parent_info(m_snap_id);
+    if (parent_info == nullptr) {
+      *result = -ENOENT;
+      lderr(cct) << "failed to retrieve snapshot parent info" << dendl;
+      finalize();
+      return m_on_finish;
+    }
+
+    parent_md = *parent_info;
+    refresh_parent = RefreshParentRequest<I>::is_refresh_required(
+        m_image_ctx, parent_md, m_image_ctx.migration_info);
+  }
+
+  if (!refresh_parent) {
+    if (m_snap_id == CEPH_NOSNAP) {
+      // object map is loaded when exclusive lock is acquired
+      *result = apply();
+      finalize();
+      return m_on_finish;
+    } else {
+      // load snapshot object map
+      return send_open_object_map(result);
+    }
+  }
+
+  ldout(cct, 10) << __func__ << dendl;
+
+  using klass = SetSnapRequest<I>;
+  Context *ctx = create_context_callback<
+    klass, &klass::handle_refresh_parent>(this);
+  m_refresh_parent = RefreshParentRequest<I>::create(m_image_ctx, parent_md,
+                                                     m_image_ctx.migration_info,
+                                                     ctx);
+  m_refresh_parent->send();
+  return nullptr;
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::handle_refresh_parent(int *result) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << ": r=" << *result << dendl;
+
+  if (*result < 0) {
+    lderr(cct) << "failed to refresh snapshot parent: " << cpp_strerror(*result)
+               << dendl;
+    finalize();
+    return m_on_finish;
+  }
+
+  if (m_snap_id == CEPH_NOSNAP) {
+    // object map is loaded when exclusive lock is acquired
+    *result = apply();
+    if (*result < 0) {
+      finalize();
+      return m_on_finish;
+    }
+
+    return send_finalize_refresh_parent(result);
+  } else {
+    // load snapshot object map
+    return send_open_object_map(result);
+  }
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::send_open_object_map(int *result) {
+  if (!m_image_ctx.test_features(RBD_FEATURE_OBJECT_MAP)) {
+    *result = apply();
+    if (*result < 0) {
+      finalize();
+      return m_on_finish;
+    }
+
+    return send_finalize_refresh_parent(result);
+  }
+
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << dendl;
+
+  using klass = SetSnapRequest<I>;
+  Context *ctx = create_context_callback<
+    klass, &klass::handle_open_object_map>(this);
+  m_object_map = ObjectMap<I>::create(m_image_ctx, m_snap_id);
+  m_object_map->open(ctx);
+  return nullptr;
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::handle_open_object_map(int *result) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << ": r=" << *result << dendl;
+
+  if (*result < 0) {
+    lderr(cct) << "failed to open object map: " << cpp_strerror(*result)
+               << dendl;
+    m_object_map->put();
+    m_object_map = nullptr;
+  }
+
+  *result = apply();
+  if (*result < 0) {
+    finalize();
+    return m_on_finish;
+  }
+
+  return send_finalize_refresh_parent(result);
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::send_finalize_refresh_parent(int *result) {
+  if (m_refresh_parent == nullptr) {
+    finalize();
+    return m_on_finish;
+  }
+
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << this << " " << __func__ << dendl;
+
+  using klass = SetSnapRequest<I>;
+  Context *ctx = create_context_callback<
+    klass, &klass::handle_finalize_refresh_parent>(this);
+  m_refresh_parent->finalize(ctx);
+  return nullptr;
+}
+
+template <typename I>
+Context *SetSnapRequest<I>::handle_finalize_refresh_parent(int *result) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << this << " " << __func__ << ": r=" << *result << dendl;
+
+  if (*result < 0) {
+    lderr(cct) << "failed to close parent image: " << cpp_strerror(*result)
+               << dendl;
+  }
+  finalize();
+  return m_on_finish;
+}
+
+template <typename I>
+int SetSnapRequest<I>::apply() {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << __func__ << dendl;
+
+  std::scoped_lock locker{m_image_ctx.owner_lock, m_image_ctx.image_lock};
+  if (m_snap_id != CEPH_NOSNAP) {
+    ceph_assert(m_image_ctx.exclusive_lock == nullptr);
+    int r = m_image_ctx.snap_set(m_snap_id);
+    if (r < 0) {
+      return r;
+    }
+  } else {
+    std::swap(m_image_ctx.exclusive_lock, m_exclusive_lock);
+    m_image_ctx.snap_unset();
+  }
+
+  if (m_refresh_parent != nullptr) {
+    m_refresh_parent->apply();
+  }
+
+  std::swap(m_object_map, m_image_ctx.object_map);
+  return 0;
+}
+
+template <typename I>
+void SetSnapRequest<I>::finalize() {
+  if (m_writes_blocked) {
+    m_image_ctx.io_image_dispatcher->unblock_writes();
+    m_writes_blocked = false;
+  }
+}
+
+template <typename I>
+void SetSnapRequest<I>::send_complete() {
+  finalize();
+  m_on_finish->complete(0);
+  delete this;
+}
+
+} // namespace image
+} // namespace librbd
+
+template class librbd::image::SetSnapRequest<librbd::ImageCtx>;